How is the flu virus spread in the air?

Answer 1

By inhaling contaminated droplets.

Answer 2

Influenza goes from person to person through close contact and direct touch, indirect touch, or respiratory droplets in the air carrying the virus short distances from person to person or from person to environmental surfaces through coughs and sneezes. If you touch where a person with flu touches, you will most likely pick up the virus and get the flu, too. That is how it spreads indirectly. Stay a minimum of six feet away from someone with a known infection and avoid close contact from being in crowded places.

You get direct spreading when you have skin to skin contact or direct person to person contact with an infected individual, such as shaking hands, kissing, or caring for a child or other infected person with hands-on care. You could be infected by getting too close to someone who has it. Do not hug people who have the flu. Wait for them to recover, then hug them (a lot).

Do not share drinking glasses or eating utensils with someone, this can also spread the disease. There is some evidence to suggest that it can be spread through gastrointestinal means, such as saliva, emesis (vomit), and feces (stool).

The importance of hand washing before and after eating, using the restroom, or providing personal care to an infected individual can not be over stressed. Avoid putting your hands in your mouth and nose or rubbing your eyes before washing your hands. Teach your family proper hand washing technique. (See related question for this information).

Flu viruses enter the body through the mucous membranes - the eyes, the nose or the mouth. They go from person to person through close contact and direct touch, indirect touch, or respiratory droplets containing the virus being ejected through coughs and sneezes from person to person or from person to environmental surfaces.

If you touch where a person with flu touches, you will most likely pick up the virus and get the flu. That is how it spreads indirectly. Stay a minimum of six feet away from someone with a known infection, avoid close contact from crowded places. The six foot guideline is based on how far respiratory droplets can go before falling to the floor or other surfaces. They do not actually float in the air to be an airborne pathogen. The respiratory droplets that carry the virus particles come from a sneeze or cough of an infected person.

Flu viruses can also be spread by handling money soon after an infected person touched it.

Flu is not spread through swimming in chlorinated pools, or by being in the water at recreational water parks that regularly treat the water. It is not spread in fountains that use purified water or in spas. There is some risk of catching it at beaches, or at recreational water theme parks from people among the crowds and not in the treated water, just as in any other crowded public place.

Protect yourself and others by getting your flu vaccination, it is the most important and most effective way to stay well and to avoid spreading the flu to your family, coworkers, and in public. Flu vaccines, as currently made, have been proven to be safe and effective over decades of use.

Another very important method of prevention is proper and frequent hand washing and regular hygiene. To help prevent the flu, wash your hands frequently with soap and warm water, and avoid touching your face, eyes, nose, and mouth. When you have the virus on your hands and touch the tissues in those places, that is how the virus enters your body.

How Long Can You Spread It When Infected?

There are still studies in progress to determine the best answer to this question. A commonly accepted guideline stipulates that one should be suspected to be capable of still spreading the flu until 24 hours after the fever subsides [while taking no fever reducers]. This is the guideline suggested by the CDC and WHO.

Testing of Swine Flu in one study using a very sensitive test to detect virus in the nose or throat found that 80 percent had it five days after symptoms began, and 40 percent seven days after. Some still harbored virus as long as 16 days later. How soon they started on antiviral medicines such as Tamiflu made a difference in how much virus was found, but not whether virus was present at all. For best results Tamiflu and other antiviral medicines should be started within 40 hours of the first symptoms, according to the most recent findings.

Doctors know that people can spread ordinary seasonal flu for a couple of days before and after symptoms start by studying viruses that patients shed in mucus. The first such studies of swine flu imply a longer contagious period.

Answer 3

Coughing and sneezing by an infected person are the most common sources of the spread of influenza on respiratory droplets in the air.

Flu viruses (including A-H1N1/09) can be on respiratory droplets for a short time in the air and then inhaled if you are within six feet of the person who coughed or sneezed. The droplets in the air carrying the virus will typically quickly fall to surfaces within that six foot radius. Once they are on the surfaces, they are easily picked up on hands and then from there transferred to another person or yourself (when the viruses from the surface come in contact with mucus membrane tissue in the nose, mouth, or eyes).

Most of the indications in clinical settings suggest that the flu virus is not significantly "airborne", according to the medical use of that word. Airborne in that sense would mean that it is in the air and stays in the air to move on air currents over distances greater than a few feet. There is some debate on this, but the guidelines for prevention of the spread of influenza from the World Health Organization (WHO), Centers for Disease Control and Prevention (CDC), National Health Service (NHS) in the UK, and other infectious disease control and research organizations, include much more information concerned with the virus being spread by direct contact (e.g., on the hands) and from spread on respiratory droplets, instead of by a truly "airborne" route.

Different time frames are found referenced about the length of time viruses can remain viable on surfaces outside a living host. For most environments, it is often quoted that they can "live" for 24 to 48 hours on nonporous environmental surfaces. They quote that they live less than 12 hours on porous surfaces, before becoming inert.

For the most effective protection against a direct transmission, it is recommended that you use good hygiene, and especially hand washing with warm water and soap (or use hand sanitizers that are minimally 60% alcohol according to the product directions for use). In addition, the agencies mentioned above recommend that you maintain a distance of six feet from an infected person. This is far enough to be out of range of their sneezing or coughing (or otherwise producing respiratory droplets, such as during speaking). Avoid touching surfaces and items the infected person has touched. Whenever possible, avoid crowded places.

Like the seasonal flu, H1N1/09 it is mainly transmitted person-to-person through direct skin-to-skin contact, or through the spread on respiratory droplets from coughing or sneezing by people infected with the influenza virus.

Are masks helpful?

You can wear a "respirator" mask (a common type is known as N-95). These are worn on your face to filter the virus particles and prevent you from inhaling them. They must be fitted to your face according to specific medical fitting guidelines. They are not recommended for children or men with beards due to fitting difficulties which would allow the virus to enter around the sides of the N-95 mask. The plain surgical masks that were often seen being worn on the streets at the beginning of the H1N1 pandemic are not effective in filtering out the sub-microscopic virus. The virus will pass right through those masks or around the edges. The respirators can also be problematic for people with Asthma, or others with respiratory disease, since they are difficult for some people to breathe through them.

The surgical type of face masks are most effective as a means to cover the mouth and nose of infected people so that, like using a tissue, their coughs or sneezes will be contained. These may also be effective for others to prevent respiratory droplets from being inhaled, such as health care workers, caregivers, or parents who must be within that very close proximity to the ill person. Droplets may directly infect those within three feet of the ill person if no mask is used.

All types of face masks and respirators should be used only once and then carefully disposed of in trash containers, washing hands afterward. Some masks become ineffective when damp from perspiration or humid air from respiration after a period of use, and may need to be changed to remain effective (see guidelines for use given with each device).

There are some who believe that the influenza virus also poses a threat as an airborne particle under specific environmental conditions, and who recommend filtration and purification systems for use with HVAC systems in buildings and homes. The necessity of these for use in non-clinical public settings, and residential settings is questioned by other researchers. WHO, CDC, and others do not specify use of these in their prevention recommendations.

Modes of Transmission

In an August 21, 2009 document on Swine Flu Infection Control Considerations from the Center for Infectious Disease Research & Policy (CIDRAP) at the University of Minnesota, they stated:

"Influenza viruses potentially can be transmitted through droplet, contact, and airborne modes. Although existing data are limited regarding the contribution of each mode of transmission, a recent review concluded that influenza virus transmission occurs at close range rather than over long distances (see References: Brankston 2007)."

"Droplet transmission

• Influenza viruses are predominantly transmitted by large droplets (ie, >5 mcm).

• Droplets are expelled by coughing and sneezing and generally travel through the air no more than 3 feet from the infected person.

• Transmission via large droplets requires close contact between the source and recipient persons, permitting droplets, which do not remain suspended in the air, to come into direct contact with oral, nasal, or ocular mucosa.

• Special air handling and ventilation systems are not required to prevent droplet transmission."

"Airborne transmission

• Airborne transmission of influenza viruses (i.e., transmission via droplet nuclei [<5 mcm], which remain suspended in the air and have the potential to travel farther than several feet) has been suggested in several reports, although evidence to conclusively support airborne transmission of influenza virus is limited (see references, Bridges 2003)."

• Available data suggest that airborne transmission does not play a major role in the spread of influenza viruses. . .However, airborne transmission of influenza viruses may occur, at least over short distances, and further study is needed to determine the importance of this mode of transmission in healthcare or other settings.

• There is no evidence to date that droplet nuclei containing influenza viruses can travel through ventilation systems or across long distances, such as can occur with tuberculosis and certain other viral agents."

In a research paper, published in 2003 in the Chicago Journals, Transmission of Influenza: Implications for Control in Health Care Settings, by Carolyn Buxton Bridges, et al, (see link below) the following excerpts were found:

"Airborne transmission entails the production of infectious droplet nuclei, generally <5 μm in diameter, which, in contrast to droplets, can remain suspended in the air and be disseminated by air currents in a room or through a facility to be inhaled by a susceptible host. Preventing the spread of droplet nuclei requires the use of special air‐handling and ventilation procedures."

"Evidence exists to support the transmission of influenza viruses by direct and indirect contact and by droplet and droplet nuclei (i.e., airborne) transmission. However, experimental studies involving humans are limited, and the relative contribution of each mode of transmission remains unclear. Furthermore, the relative importance of airborne transmission in a setting of normal air exchange is unknown."

Transmission of influenza A in Human Beings, by Gabrielle Brankston MHSc, et al, published in 2007 in The Lancet gave further information about the airborne transmission of Influenza viruses. This excerpt is from that paper:

"Despite vast clinical experience in human beings, there continues to be much debate about how influenza is transmitted. We have done a systematic review of the English language experimental and epidemiological literature on this subject to better inform infection control planning efforts. We have found that the existing data are limited with respect to the identification of specific modes of transmission in the natural setting. However, we are able to conclude that transmission occurs at close range rather than over long distances, suggesting that airborne transmission, as traditionally defined, is unlikely to be of significance in most clinical settings. Further research is required to better define conditions under which the influenza virus may transmit via the airborne route."

Answer 4

it doesnt it is caused by wind and breeze of the outer atposphere

Answer 5

by droplet infection